1. Field of the Invention
The present invention relates to a method for resolving parameters of DRAM (Dynamic Random Access Memory), and more particularly, to a method for testing an untested DRAM parameter set to an untested predetermined value to initialize the DRAM.
2. Description of the Prior Art
During computer initialization the data stored in the BIOS (Basic Input/Output System) is copied to DRAM (Dynamic Random Access Memory). A DRAM initialization is required for the host to acquire the DRAM capacity. In the prior art, the BIOS reads the SPD (Serial Presence Detect) directly from the DRAM and gets all necessary date for DRAM initialization. SPD is an EEPROM (Electrically Erasable Programmable Read-Only Memory) device of smaller size than normal DRAM. SPD contains data of 128-byte length. Each byte represents a specific meaning, indicating detailed DRAM information, including DRAM size, DRAM type, performance parameters, vendor information, etc. In the prior art, the BIOS reads the chip number, the DIMM (dual inline memory module) number, DRAM bank number, the bank interleave parameter, the DRAM timing parameter, the DRAM driving parameter, etc. directly from the SPD of the DRAM. The data read from the SPD is used to set all DRAM parameters and the DRAM initialization is processed based on this DRAM parameter setting.
However, if the DRAM parameters are set based on the wrong data directly read from the SPD, it can lead to DRAM initialization failure. Especially when the DRAM timing parameter and the operating frequency parameter are set to wrong values, the whole system can crash. Or, if the information stored on the SPD is altered using a special write/read device, the BIOS will then get wrong information, which is a hidden danger in computer applications, especially in server DRAMS.